Phonological development in lexically precocious 2-year-olds by Smith, McGregor & Demille Presented by: Marrian B. Bufete

Abstract To examine interactions between young children’s vocabulary size and their phonological abilities, spontaneous language samples were collected from 24-year-olds with precocious lexicons, their age mates (24-month-old with average sized- lexicons) and their vocabulary mates (30-month- olds with average-sized lexicons).

Phonological abilities were measured in a variety of ways such as the number of different consonants that were targeted the number of different consonants produced correctly, and the occurrence of phonological processes. The lexically precocious 24-moth-olds were similar to their vocabulary mates on most measures of phonological ability, and both of these groups were generally superior to the 24-month-olds with smaller lexicons.

These findings supported a hypothesized relationship between lexicon size and phonological performance, and demonstrated that 2-year-olds’ phonological development is more closely related to size of the lexicon than chronological age.

This study aims to examine the correlationship between the young children’s vocabulary size and their phonological abilities. To analyze young (2-year-old) children's phonetic and phonological abilities from a more naturalistic perspective.

One purpose of the present investigation, therefore, was to examine phonological patterns of several groups of children representing a range from average to precocious lexical development.

Related Literature Studies conducted by Edwards et al., (2004) and Garlock, Walley, & Metsala (2001) on the relationship existing between a child’s lexicon and his/her phonological system and the current theories that emphasized the interrelatedness of phonology and the lexicon development.

Recent research utilizing gaze fixation procedures indicates that in the first year of life, infants appear to “…perform statistical analyses of distributions of sounds they hear, thereby learning categories that form the basis of the child’s phonology” (Swingley, 2005b, p.87).

Gathercole et al. (1997) found that 5-year olds with larger expressive and receptive vocabularies were able to repeat non words more accurately than peers with smaller vocabularies. Given that non words have no meaning associated with them, this finding suggests there’s a relationship between the size of a child’s lexicon and his/her short-term phonological memory.

Method Participants To examine potential relationships between lexicon size and productive phonological development, spontaneous language samples were collected from 51 2-year-old children (29 girls, 24 boys), who were recruited from the north shore of Chicago (a predominantly middle

to upper class area) by personal referrals and through newspaper advertisements. With the exception of three children suspected to have phonological disorders, all children that were recruited were entered into the study. They were subsequently divided into subgroups according to age (either 24 0r 30 months) and vocabulary size (average or precocious; this distinction is described in greater detail).

1 st group 24-month-olds with average lexicons 2 nd group 24-month-olds with advanced/ precocious lexicons (i.e., an age- matched group for the first group

3 rd group 30-month-olds with average size lexicons that were approximately the same size as those of the advanced 24-month-old children’s Lexicons (i.e., a vocabulary- matched group for the precocious 24-month-olds

Group 1 15 had a mean age of 2 years, o months (2:0 range=1:11-2:1) -classified as “average” talkers -designated as the 24/AV group (age/CDI) CDI-Mac Arthur Communicative Development Inventory (manual)

Group 2 -classified as “precocious” talkers -mean vocabulary size was 590 words which is greater than the average lexicon size of the age- matched, typical talkers (24/AV).

Group 3 -consisted of 14 talkers, who had a mean age of 2:6 (range=2:5-2:7) words which was quite similar to that of the 24/Pr group’s average -30-month-old children (designated as 30/Av) was included as a vocabulary-matched comparison group for the 24/Pr children.

Primary comparisons were made between: -two groups of 24-month-olds that varied according to lexicon (24/Av and 24/Pr) -the 30-month-olds with typical lexicon sizes (30/Av)

24/Pr group and 24/Av 24/Pr group and 30/Av

Data Collection Each participant came to the Child Language Laboratory at Northwestern University with a parent for a visit of approximately 1 hr.

Data Analysis The various analyses that were selected included the following: 1. Number of singleton consonants targeted 2. Number of singleton consonants correct at least one time

3. Number of consonants produced with at least 75% accuracy 4. Percentage of correct consonants (PPC) 5. Phonological processes